Military rank is a system of hierarchical relationships in armed forces or civil institutions organized along military lines. Usually, uniforms denote the bearer's rank by particular insignia affixed to the uniforms. Ranking systems have been known for most of military history to be advantageous for military operations, in particular with regards to logistics, command, and coordination; as time continued and military operations became larger and more complex, military ranks increased and ranking systems themselves became more complex.
Within modern armed forces, the use of ranks is almost universal. Communist states have sometimes abolished rank (e.g. the Soviet Russian Red Army 1918–1935, the Chinese People's Liberation Army 1965–1988, and the Albanian Army 1966–1991) only to re-establish them after encountering operational difficulties of command and control.
The army of ancient Persia consisted of manageable military groupings under individual commands. Starting at the bottom, a unit of 10 was called a dathabam and was led by a dathapatish. A unit of 1,000 was a hazarabam and was commanded by a hazarapatish. A unit of 10,000 was a baivarabam and was commanded by a baivarapatish. The Greeks called such masses of troops a myrias or myriad. Among mounted troops, an asabam was a cavalry unit led by an asapatish.
Below this was the syntagmatarkhis, which can be translated as "leader of a regiment" (syntagma) and was therefore like a modern colonel. Below him was the tagmatarkhis, a commanding officer of a tagma (near to the modern battalion). The rank was roughly equivalent to the legatus of a Roman legion. Next was the lokhagos, an officer who led an infantry unit called a lokhos that consisted of roughly a hundred men, much the same as in a modern company led by a captain.
In ancient Greece, a Greek cavalry (hippiko) regiment was called a hipparchia and was commanded by a hyparchos or hipparch, but Spartan cavalry was led by a hipparmostes. A hippotoxotès was a horse archer. A Greek cavalry company was led by a tetrarchès or tetrarch.
The rank and file of the military in most of the Greek city states was composed of ordinary citizens. Heavily armed foot soldiers were called hoplitès or hoplites and a hoplomachos was a drill or weapons instructor.
Once Athens became a naval power, the top generals of the land armies had authority over the naval fleets as well. Under them, each warship was commanded by a trièrarchos or trierarch, a word which originally meant "trireme officer" but persisted when other types of vessels came into use. Moreover, as in modern navies, the different tasks associated with running a ship were delegated to different subordinates. Specifically, the kybernètès was the helmsman, the keleusthès managed the rowing speed, and the trièraulès was the flute player who maintained the strike rate for the oarsmen. Following further specialization, the naval strategos was replaced by a nauarchos, a sea officer equating to an admiral.
With the rise of Macedonia under Philip II of Macedon and Alexander the Great, the Greek military became professional, tactics became more sophisticated and additional levels of ranking developed. Foot soldiers were organized into heavy infantry phalanxes called phalangites. These were among the first troops ever to be drilled, and they fought packed in a close rectangular formation, typically eight men deep, with a leader at the head of each column (or file) and a secondary leader in the middle so that the back rows could move off to the sides if more frontage was needed.
A tetrarchia was a unit of four files and a tetrarchès or tetrarch was a commander of four files; a dilochia was a double file and a dilochitès was a double-file leader; a lochos was a single file and a lochagos was a file leader; a dimoiria was a half file and a dimoirites was a half-file leader. Another name for the half file was a hèmilochion with a hèmilochitès being a half-file leader.
Different types of units, however, were divided differently and therefore their leaders had different titles. For example, under a numbering system by tens, a dekas or dekania was a unit of ten led by a dekarchos, a hekatontarchia was a unit of hundred led by a hekatontarchès and a chiliostys or chiliarchia was a unit of a thousand led by a chiliarchès.
The cavalry, for which Alexander became most famous (in a militarily sense ), grew more varied. There were heavy cavalry and wing cavalry (ilè) units, the latter commanded by an ilarchès.
The tribuni militari were the Roman army's senior officers who commanded the rough equivalents to the US and British armies battalions and brigades (the relevant modern ranks being major, lieutenant colonel, colonel and brigadier general). Note that these comparisons are only loose because the Roman army's command structure was much different from the organizational structure of its modern counterparts, which arose from the medieval mercenary companies, rather than from the writings of Fourth Century Roman writer Vegetius and Caesar's commentaries on his conquest of Gaul and the civil war.
The term military tribune is sometimes translated into English as "colonel" — most notably by the late classicist Robert Graves in his "Claudius" novels and his translation of Suetonius' Twelve Caesars — to avoid confusion with the political "tribunes of the people."
The fighting men in the legion were formed into ranks, rows of men who fought as a unit. Under Marius's new system, legions were divided into ten cohorts (cohortes), each consisting of six centuries, each of between 60 and 160 men. Each century was led by a centurion (centurio) who was assisted by a number of junior officers. Centuries were further broken into ten contubernia of eight soldiers each. Individual soldiers were referred to as soldiers (milites) or legionaries (legionarii).
Roman discipline was severe, with all ranks subject to corporal and capital punishment at the commander's discretion. For example, if a cohort broke in battle, the typical punishment was decimation, in which every tenth soldier, selected by lot, was killed.
The basic unit of the medieval army was the company, a band of soldiers assigned (or raised) by a vassal lord on behalf of his lord (in later times the King himself). The vassal lord in command of the company was a commissioned officer with the rank of captain. Captain was derived from the Late Latin word capitaneus (meaning head man or chief).
The commissioned officer assisting the captain with command of the company was the lieutenant. Lieutenant was derived from the French language; the lieu meaning “place” as in a position; and tenant meaning “holding” as in “holding a position”; thus a “lieutenant” is somebody who holds a position in the absence of his superior. When he was not assisting the captain, the lieutenant commanded a unit called a platoon, particularly a more specialized platoon. The word is derived from the 17th-century French peloton, meaning a small ball or small detachment of men, which came from pelote, a ball.
The commissioned officer carrying the (infantry) company’s flag was the ensign. The word ensign was in fact derived from the Latin word insignia. In cavalry companies the equivalent rank was cornet. In English usage, these ranks were merged into the single rank of Second Lieutenant in the 19th Century.
Not all officers received a commission from the King. Certain specialists were granted a warrant, certifying their expertise as craftsmen. These warrant officers assisted the commissioned officers but ranked above the noncommissioned officers.
A received their authority from superior officers rather than the King. The highest rank of NCO was sergeant. The first sergeants were the armed servants (men-at-arms) of the aristocracy, assigned to command, organize and train the militia units raised for battle. After years of commanding a squad, a NCO could be promoted to sergeant. While a sergeant might have commanded a squad upon promotion, he usually became a staff officer. While commissioned staff officers assisted their commander with personnel, intelligence, operations and logistics, the sergeant was a jack of all trades, concerning himself with all aspects of administration to maintain the enlisted men serving under his commander. Over time, sergeants were differentiated into many ranks as various levels of sergeants were used by the commanders of various levels of units.
A corporal commanded a squad. Squad derived from the Italian word for a “square” or “block” of soldiers. In fact, corporal was derived from the Italian caporal de squadra (head of the squad). Corporals were assisted by lancepesades. Lancepesades were veteran soldiers; lancepesade was derived from the Italian lanzia spezzata meaning broken spear - the broken spear being a metaphor for combat experience, where such an occurrence was likely. The first lancepesades were simply experienced privates; who either assisted their corporal or performed the duties of a corporal themselves. It was this second function that made armies increasingly regard their lancepesades as a grade of corporal rather than a grade of private. As a result, the rank of Lance Corporal was derived from combining lancepesade and corporal.
As the Middle Ages came to an end, kings increasingly relied on professional soldiers to fill the bottom ranks of their armies instead of militiamen. Each of these professionals began their careers as a private. The private was a man who signed a private contract with the company commander, offering his services in return for pay. The money was raised through taxation; those yeomen (smallholding peasants) who did not fulfill their annual 40-day militia service paid a tax that funded professional soldiers recruited from the yeomanry. This money was handed to the company commanders from the royal treasury, the company commanders using the money to recruit the troops.
As armies grew larger, composed of multiple companies, one captain was granted general (overall) authority over the field armies by the King. (National armies were the armies of the kings. Field armies were armies raised by the King to enter the battle field in preparation for major battles.) In French history, “lieutenant du roi” was a title borne by the officer sent with military powers to represent the king in certain provinces. A lieutenant du roi was sometimes known as a lieutenant general to distinguish him from lieutenants subordinate to mere captains. The sergeant acting as staff officer to the captain general was known as the sergeant-major general. This was eventually shortened to major general, while captain general was shortened to simply general. This is the reason why a major outranks a lieutenant, but a lieutenant general outranks a major general.
As armies grew bigger, they were split into corps. The lieutenant generals received command of these corps. The corps were split into divisions, each division headed by a major general. The division was originally an organizational structure under the corps to assist in command and control of various regiments and brigades. The corps remained the primary maneuver unit of the army, while heraldry and unit identification remained primarily a matter of the regiment. Brigades headed by brigadier generals were the units invented as a tactical unit, by the Swedish king Gustavus Adolphus. It was introduced to overcome the normal army structure, consisting of regiments. The so-called “brigada” was a mixed unit, comprising infantry, cavalry and normally artillery too, designated for a special task. The size of such “brigada” was a reinforced company up to two regiments. The “brigada” was a 17th century form of the modern “task force”.
Around the end of the 16th century, companies were grouped into regiments. The officers commissioned to lead these regiments were in fact called colonels (column officers). They were first appointed in Spain by King Ferdinand II of Aragon where they were also known as coronellos (crown officers) since they were appointed by the Crown. Thus the English pronunciation of the word colonel.
The first colonels were captains granted command of their regiments by commission of the King. The lieutenants of the colonel were the lieutenant colonels. In the 17th century, the sergeant of the colonel was the sergeant major. These were field officers, third in command of their regiments (after their colonels and lieutenant colonels), with a role similar to the older, army-level sergeant majors (although obviously on a smaller scale). The older position became known as sergeant major general to distinguish it. Over time, the sergeant was dropped from both titles since both ranks were used for commissioned officers. This gave rise to the modern ranks of major and major general.
The full title of sergeant major fell out of use until the latter part of the 18th century, when it began to be applied to the senior non-commissioned officer of an infantry battalion or cavalry regiment.
Apart from conscripted personnel one can distinguish:
Officers are further separated into Four levels as with the Canadian Forces:
General Officer ranks typically include (from the top down) General, Lieutenant General, Major General, and Brigadier General, although there are many variations like Division General or (Air-, Ground-) Force General.
Flag Officer ranks, named after the traditional practice of showing the presence of such an officer with a flag on a ship and often land, typically include (from the top down) Admiral, Vice Admiral and Rear Admiral. In some navies, such as Canada's, the rank of Commodore is a flag rank.
In the United Kingdom and most other Commonwealth air forces, Air Officer ranks usually include Air Chief Marshal, Air Marshal, Air Vice-Marshal and Air Commodore. For some air forces, however, such as those of Canada, United States or most of the Air Forces in the Americas, army General Officer ranks are used.
In some forces there may be one or more superior ranks to the common examples, above, that are given distinguishing titles, such as Field Marshal or General of the Armies (many armies), Fleet Admiral (U.S. Navy), Marshal of the Royal Air Force, or other national air force. These ranks have often been discontinued, such as in Germany and Canada, or limited to wartime and/or honorific promotion, such as in the United Kingdom and the United States.
In various countries, particularly the United States, these may be referred to as "star ranks" for the number of stars worn on some rank insignia: typically one star for Brigadier General or equivalent with the addition of a star for each subsequent rank. In the United States five stars has been the maximum used in all services (excluding the Marines and Coast Guard which have only used four). (However, see General of the Armies of the United States for a theoretically "six-star" rank held by John J. Pershing and to which George Washington was posthumously promoted.)
Some titles are not genuine ranks, but either functions assumed by generals or honorific titles. For instance, in the French Army Général de corps d'armée is a function assumed by some Généraux de division, and Maréchal de France which is a distinction denoting the most superior military office, but one that has often neutered the practical command powers of those on whom it is conferred. In the United States Navy, a commodore currently is a senior captain commanding a squadron that is too small for a rear admiral to command, although that name has historically been used as a rank.
The term "field(-grade) officer" is primarily used by armies and Marines; air forces and navies generally prefer the term "senior officer." The two terms are not necessarily synonymous.
Typical army and Marine Field Officer ranks include Colonel (/ˈkɹ̩nl̩/), Lieutenant Colonel, Major and Captains in the British Army holding an Adjutant's appointment. In many Commonwealth countries the field rank of Brigadier is used, although it fills the position held by Brigadier General in other countries.
USN naval senior officer ranks include captain and commander. In some countries, the more senior rank of commodore is also used, a position that follows the flag flying tradition (above) of flag officers but through the use of a dove-tail pennant of rank instead of the flag or triangular pennant of other senior officers.
Typical army company officer ranks include Captain and various grades of Lieutenant. Typical naval junior officer ranks include grades of Lieutenant Commander, Lieutenant and/or Sub-Lieutenant/Ensign. Commonwealth (excluding Canada) air force Junior Officer ranks usually include Flight Lieutenant, Flying Officer, and Pilot Officer.
"The [U.S.] commissioned officer corps is divided into 10 pay grades (O-1 through O-10). Officers in pay grades O-1 through O-3 are considered company grade officers. In the Army, Marine Corps, and Air Force, these pay grades correspond to the ranks of second lieutenant (O-1), first lieutenant (O-2), and captain (O-3), and in the Navy, ensign, lieutenant junior grade, and lieutenant. Officers in the next three pay grades (O-4 through O-6) are considered field grade officers. In the Army, Marine Corps, and Air Force, these pay grades correspond to the ranks of major (O-4), lieutenant colonel (O-5), and colonel (O-6), and in the Navy, lieutenant commander, commander, and captain. The highest four pay grades are reserved for general officers in the Army, Marine Corps, and Air Force, and flag officers in the Navy. The ranks associated with each pay grade are as follows: in the Army, Marine Corps, and Air Force, brigadier general (O-7), major general (O-8), lieutenant general (O-9), and general (O-10); in the Navy, rear admiral-lower half, rear admiral-upper half, vice admiral, and admiral.
Even the most senior NCO officially ranks beneath the most junior commissioned officer or warrant officer. However, most senior NCOs have more experience, possibly including combat, than junior officers. In some organizations, senior NCOs may have formal responsibility and informal respect beyond that of junior officers, but less than that of warrant officers. Many warrant officers come from the ranks of mid-career NCOs. In some countries warrant ranks replace senior enlisted ranks.
NCO ranks typically include a varying number of grades of Sergeant and Corporal (Air Force, Army and Marines), or Chief Petty Officer and Petty Officer (Navy and Coast Guard). In many navies the term rate is used to designate specialty, while rank denotes paygrade.
NCOs are appointed by an instrument of appointment, a written document, often a certificate, usually from the service head. Entry into service is often referred to as enlistment throughout the English speaking world, even in countries where soldiers do not technically enlist.
Sometimes personnel serve in an appointment which is higher than their actual rank. For instance, commodore used to be an appointment of captain in the Royal Navy and lance corporal used to be an appointment of private in the British Army.
Under this system, starting from the bottom and working up, a Corporal leads a Fireteam consisting of three other Marines. A Sergeant leads a Squad consisting of three Fireteams. As a result, a full squad numbers 13 individuals. Squads usually have numbered designations, i.e.: 1st Squad.
A Lieutenant commands a Platoon, which can consist of three or four Squads. In Marine infantry units, Rifle Platoons usually consist of three Rifle Squads of 13 men each, with a Navy Corpsman, the Platoon Commander, and a Platoon Sergeant (a Staff Sergeant who serves as Executive Officer). A Weapons Platoon replaces the three squads with a 60 mm mortar section, an assault section, and a medium machine gun section. An infantry Platoon can number from 42 to 55 individuals, depending on the service. Platoons are usually numbered (i.e.: 1st Platoon) or named after their primary function (i.e.: Service Platoon).
A Captain commands a Company, usually consisting of four Platoons (three Rifle Platoons and one Weapons Platoon). His command post can include a Gunnery Sergeant and as many as seven others. So a Company can comprise from roughly 175 to 225 individuals. Equivalent units also commanded by Captains are Batteries and Detachments. In English speaking countries, a Company (or troop in the Cavalry or Armor, and Battery in the Artillery) is usually designated by a letter, i.e.: A Company. In non-English speaking countries, they are usually numbered.
A Lieutenant Colonel commands a Battalion or a Squadron, often consisting of four Companies or Sections plus the various members of his command post. A battalion is around 500-1500 men and usually consists of between two and six companies.
A Colonel commands a Regiment or Group, often consisting of four Battalions (for an Infantry unit) or five to six Air Groups (for a Wing). Battalions and Regiments are usually numbered, either as a separate Battalion or as part of a Regimental structure, i.e.: 1/1 Marines in the Marine Corps or 1-501st Infantry in the US Army.
In these latter, abstractions cease to be helpful and it becomes necessary to turn to an actual unit. The 1st Battalion of the 1st Marine Regiment of the 1st Marine Division of the I Marine Expeditionary Force consists of three infantry companies, one weapons company, and one headquarters and service company. Above that, the 1st Marine Regiment (First Marines) consists of four such Battalions and one headquarters company. Marine Air Control Group 18 of 1st Marine Air Wing of the III Marine Expeditionary Force consists of four squadrons, one battery, and one detachment, a mix of different-sized units under a regimental equivalent-sized unit.
The next level has traditionally been a Brigade, commanded by a Brigadier General, and containing two or more Regiments. But this structure is considered obsolete today. At the present time, in the U.S. Army, a Brigade is roughly equal to or a little larger than a Regiment, consisting of three to seven battalions. Strength typically ranges from 1,500 to 3,500 personnel. In the U.S. Marines, Brigades are only formed for certain missions. In size and nature they are larger and more varied collections of Battalions than is common for a Regiment, fitting them for their traditional role as the smallest formation able to operate independently on a battlefield without external logistical tactical support. Brigades are usually numbered, i.e.: 2d Brigade.
The level above Regiment and Brigade is the Division, commanded by a Major General and consisting of from 10,000 to 20,000 persons. The 1st Marine Division, for example, is made up of four Marine Regiments (of the type described above), one Assault Amphibian Battalion, one Reconnaissance Battalion, two Light Armored Reconnaissance Battalions, one Combat Engineer Battalion, one Tank Battalion, and one Headquarters Battalion—totalling more than 19,000 Marines. (Within the Headquarters Battalion are one Headquarters Company, one Service Company, one Military Police Company, one Communications Company, and one Truck Company.) An equivalent elsewhere within the same Marine Expeditionary Force (MEF) might be a MEF Logistics Group (MLG) - which is not a regimental-sized unit (as the word "group" implies), but rather a large support unit consisting of several battalions of support personnel. Divisions are normally numbered, but can be named after a function or personage.
Considering such a variety of units, the command sizes for any given rank will vary widely. Not all units are as troop intensive as infantry forces need to be. Tank and Artillery crews, for example, involve far fewer personnel. Numbers also differ for non-combat units such as quartermasters, cooks, and hospital staff. Beyond this, in any real situation, not all units will be at full strength and there will be various attachments and detachments of assorted specialists woven throughout the system.
The 1st Marine Division is part of the I Marine Expeditionary Force, which also includes the 3rd Marine Air Wing, 1st Service Support Group, 1st Marine Expeditionary Brigade, three Marine Expeditionary Units (featuring helicopter groups), and a Battalion-sized Marine Air Ground Task Force. In the U.S. Marine Corps there are three Marine Expeditionary Forces.
In the U.S. Army, the level above Division is called a Corps instead of an Expeditionary Force. It is commanded by a Lieutenant General. In many armies, a Corps numbers around 60,000, usually divided into three divisions. Corps (and similar organizations) are normally designated with roman numerals and their nationality when operating in a Combined (international) force, i.e.: V (US) Corps, VIII (ROK) Corps, II MEF, I Canadian Corps.
During World War II, due to the large scale of combat, multiple Corps were combined into Armies commanded in theory by a General (four stars), but often by a Lieutenant General (three stars), and comprising as many as 240,000 troops. Armies are numbered by spelled-out numerals or functional titles, using their nationality in Combined forces, i.e.: Eighth (US) Army, Third (ROK) Army, British Army of the Rhine (BAOR).
These were in their turn formed into Army Groups, these being the largest field organization handled by a single commander in modern warfare. Army Groups included between 400,000 and 1,500,000 troops. Army Groups received Arabic numeral designations and national designations when Combined, i.e.: 12 (BR) Army Group.
These examples illustrate a standard that holds true all over the world and throughout history: rank generally implies size of command in a nested system of ranks and commands. But the specific size of a command for any given rank will depend on the task the unit performs, the nature of weapons used, and the strategies of warfare.